TAIF, SAUDI ARABIA, JAN. 11 -- After months of talks, Saudi Arabia has given the United States a green light if necessary to commence military operations against Iraq, according to Saudi and U.S. diplomats, who said that the next step would be for President Bush to notify Saudi officials if and when he decides to go to war.

Tonight, Secretary of State James A. Baker III told American fighter and bomber pilots and their crews deployed in Saudi Arabia that the United States will "pass the brink" of war with Iraq at midnight Tuesday, the United Nations deadline for withdrawal from Kuwait. U.S. and U.N. officials quoted during the day appeared to disagree over whether the deadline was at midnight Kuwait time or Eastern Standard Time.

Following meetings in Riyadh between Saudi King Fahd and Baker, a senior Saudi diplomat reported -- and U.S. officials confirmed -- that a phase of extensive consultations over the war decision has essentially been completed.

These consultations, which covered such issues as command and control of troops and defraying the costs of Operation Desert Shield, involved Baker, Secretary of Defense Richard B. Cheney and Gen. Colin L. Powell, chairman of the Joint Chiefs of Staff.

A senior State Department official said Bush would not need to consult further with the Saudis but could be expected to give them a "notification" of his decision if he concludes that war is necessary.

The official noted, however, that Bush has yet to make the final decision to resort to force to expel Iraq from Kuwait. Baker has said previously that any decision to fight would have to be made at the highest political levels, essentially requiring Saudi assent for any offensive. There were indications that Baker and the Saudis had discussed possible timetables for an offensive.

In an emotional appearance before about 400 uniformed airmen and women at a Saudi air base, Baker was met with cheers of gusto by troops who seemed impatient to proceed with their assignment after five months of waiting in the desert.

But, in contrast to his earlier visits, including one to the same group of airmen last autumn, Baker seemed to reflect a solemn realization that the decision to go to war may be made soon.

"Your presence here and that of many others like you -- and your preparedness and theirs -- offer the only real chance that a peaceful solution will come at the very last moment," Baker told the troops, standing before an F-111 fighter-bomber and an EF-111A Raven electronics-jamming warplane.

"As I said in Geneva, there have been too many Iraqi miscalculations," Baker said. "And we fear yet another miscalculation, a truly tragic one. We believe that if Iraq is going to withdraw from Kuwait, Saddam Hussein will probably wait until he is on the very brink before he moves. And our worry is that in his usual style, he will miscalculate where the brink exactly is."

"Just so there is no misunderstanding," Baker declared, "let me be absolutely clear: we pass the brink at midnight January 15."

His comments were the latest salvo in the U.S.-led campaign to persuade Saddam to pull out of Kuwait before the deadline. Although Baker did not say if and when the United States would go to war to expel Saddam, he used some of the toughest language yet in the effort to threaten the Iraqi president into retreat from Kuwait. And he suggested that Bush would make a decision soon about going to war.

"When I talked to you four months ago, many of you told me that you were ready. But you also asked how long before you would be called into action to undo this terrible aggression," Baker said in remarks to the 48th Tactical Fighter Wing, which includes fliers based in the United States and Britain.

"Now, as the clock ticks down to midnight January 15," he said, "I cannot give you an absolute, definitive answer. But I can tell you this -- you will not have to wait much longer for an answer to that question."

At this, the troops responded with whoops of approval.

The deadline, Baker said, "is a real deadline. Efforts to extend it or postpone it are not going to succeed. Now, Saddam can believe that or not. But if he doesn't, he will have made his most tragic miscalculation."

Baker also told the troops that he was "going to be doing all that we can to ensure that you come home safely and peacefully."

"Time is running out, but the path to peace is still open. There is still time for Iraq to walk that path," he said.

Baker recalled that he had assured Iraqi Foreign Minister Tariq Aziz that U.S. forces would not attack if Iraq pulled back. Moreover, Baker said, "Nor do we have any intention of maintaining a permanent ground presence in this region once Iraq withdraws and the threat recedes." This comment was met with a thunder of applause and cheers.

In meetings today in Riyadh, Abu Dhabi and here in Taif with the exiled Kuwaiti leadership, Baker asked for more financial aid to offset the costs of Operation Desert Shield. Saudi officals have pledged to continue their contributions. In the United Arab Emirates, officials said Baker made a presentation to President Zeid Sultan Nahayyan and his government is expected to respond later. The emir of Kuwait pledged his continued support, but amounts were not disclosed.

Also today, Baker was asked about a plan reportedly being proposed by U.N. Secretary General Javier Perez de Cuellar, envisioning an Iraqi withdrawal from Kuwait and a U.N. peace-keeping force in the region. Baker said the United States "has been talking for quite some time" about establishing "security structures" when the crisis is over.

After an Iraqi withdrawal, he said, "it would be appropriate" to consider a possible U.N. peace-keeping force as part of the effort. "I also believe, though, that the states in the region are going to have to make the greatest contribution to the security of the region."

Baker also spoke by telephone today with Luxembourg Foreign Minister Jaques Poos, who currently holds the European Community presidency, about EC peace efforts.